Unless otherwise indicated herein, the description in this section is not prior art to the claims in this application and is not admitted to be prior art by inclusion in this section.
A developer housing portion such as a toner container, which houses developer such as toner used for printing, is mounted to a typical image forming apparatus such as a printer. With this type of image forming apparatus, a user exchanges the developer housing portion at any timing. Additionally, there has been known an image forming apparatus that includes a lock mechanism. To reduce a remaining amount of developer in a developer housing portion during exchange, the lock mechanism regulates attachment/removal of the developer housing portion until a detection of the developer housing portion running out of the developer.